Sheep weren't introduced to Patagonia until the 1860s, when they were brought over from the Falkland Islands by the English wool barons. They took to the landscape with vigour, but their success has also been their downfall. They decimated the vegetation, turning much of the landscape into desert, and their numbers fell from a peak of around 7.5 million before World War II to approximately 2 million in the 1990s. The number of ranches also declined rapidly, but sheep are staging a comeback and there remain around ten sheep to every human.